Field of the Invention
The present invention relates to a drive system, in particular for a self-propelled construction machine, especially a soil compactor, comprising:
a drive unit,
at least one hydraulic circuit with a hydraulic pump drivable by the drive unit,
a hydraulic drive support unit with a hydraulic pump/motor assembly and at least one compressed fluid reservoir, wherein the hydraulic pump/motor assembly is, or can be, drivingly connected to the drive unit and/or to at least one hydraulic circuit, wherein the hydraulic pump/motor assembly is drivable in a charging operating mode as a pump by means of the drive unit and/or by means of at least one hydraulic circuit for charging at least one compressed fluid reservoir, and in a drive support state is drivable as a motor to provide a drive support torque for the hydraulic pump of at least one hydraulic circuit.
Background of the Related Art
A drive system of this kind is known from WO 2013/074164A1 as a drive system for a construction machine configured as a wheeled loader. In this known drive system, a drive unit is drivingly connected via a transmission arrangement to various hydraulic circuits. These hydraulic circuits comprise a hydraulic driving circuit with a hydraulic driving pump driven by the drive unit, and a hydraulic driving motor, which is driven by the flowing fluid when the hydraulic driving pump is operated, in order to drive the drive wheels of the wheeled loader. Furthermore, one or several hydraulic working circuits are provided. They also comprise a hydraulic working pump each, which is drivable by the drive unit via the transmission arrangement. By means of the hydraulic pressure generated by these pumps, piston/cylinder units can, for example, be activated in order to move a bucket of the wheeled loader when in operation. Furthermore, this drive system comprises a hydraulic drive support unit. Said unit comprises a hydraulic pump/motor assembly drivable by the drive unit via the transmission arrangement; said assembly charges a compressed fluid reservoir when the pump is operating, thus increasing the pressure of the fluid stored therein. The hydraulic pump/motor assembly of this hydraulic drive support unit can also be operated as a hydraulic motor in order to generate a torque by relieving the pressure in the compressed fluid reservoir, which torque can be transmitted via the transmission arrangement to the various hydraulic circuits, that is, to the hydraulic driving circuit and to the hydraulic working circuit or circuits. Thus, the hydraulic drive support unit can provide a drive support torque.